1   /* benchreg - benchmark for  register  integers
    2    * Thomas Plum, Plum Hall Inc, 609-927-3770
    3    * If machine traps overflow, use an  unsigned  type
    4    * Let  T  be the execution time in milliseconds
    5    * Then  average time per operator  =  T/major  usec
    6    * (Because the inner loop has exactly 1000 operations)
    7    */
    8   #define STOR_CL register
    9   #define TYPE int
   10   #include <stdio.h>
   11   main(ac, av)
   12           int ac;
   13           char *av[];
   14           {
   15           STOR_CL TYPE a, b, c;
   16           long d, major, atol();
   17           static TYPE m[10] = {0};
   18   
   19           major = atol(av[1]);
   20           printf("executing %ld iterations\n", major);
   21           a = b = (av[1][0] - '0');
   22           for (d = 1; d <= major; ++d)
   23                   {
   24                   /* inner loop executes 1000 selected operations */
   25                   for (c = 1; c <= 40; ++c)
   26                           {
   27                           a = a + b + c;
   28                           b = a >> 1;
   29                           a = b % 10;
   30                           m[a] = a;
   31                           b = m[a] - b - c;
   32                           a = b == c;
   33                           b = a | c;
   34                           a = !b;
   35                           b = a + c;
   36                           a = b > c;
   37                           }
   38                   }
   39           printf("a=%d\n", a);
   40           }